Denture securing apparatus



June 2, 1970 R. H. SILVERMAN 3,514,853

DENTURE SECURING APPARATUS Filed April 14, 1969 2 Sheets-Sheet l INVENTOR. RALPH H. SILVERMAN ATTY.

June 2, 1970 R. H. SILVERMAN 3,514,858

I DENTURE SECURING APPARATUS Filed April 14, 1969 z Sheets-Sheet :1

United States Patent Int. Cl. A61c 13/00 US. Cl. 32-2 11 Claims ABSTRACT OF THE DISCLOSURE Denture securing apparatus comprising a plurality of implant pins screwable into the jaw bone in the mouth of a denture wearer, and a denture including a unit structure comprising a plurality of linked cap members mounted therein. Each of the head portions of an implant pin includes a recess therein and each of the cap mem bers includes spring loaded ball bearing means. Upon the insertion of the denture into the mouth, the cap members receive respective head portions of the implant pins, and the ball bearings of the cap members are snapped into the corresponding recesses, to removably secure the denture in the mouth.

BACKGROUND OF THE INVENTION This invention relates generally to dental apparatus and more particularly to dental apparatus for retaining artificial teeth in the mouth of a human being.

Denture wearers have always experienced difficulty in retaining dentures in their mouths. Persons wearing lower dentures especially have the common problem of wobbly or unstable dentures since no natural holding force is provided by the mouth for a lower denture.

SUMMARY OF THE INVENTION Accordingly, it is a primary object of the present invention to provide new and improved apparatus for securing a denture in the mouth of a wearer.

It is a more specific object of this invention to provide a new and improved apparatus for securing a lower denture in the mouth of a wearer.

It is another object of this invention to provide denture securing apparatus of the above-described type which enables a denture wearer to easily secure and remove a denture from his mouth.

It is yet another object of this invention to provide denture securing apparatus of the tye heretofore described wherein the holding force of the denture is easily adjustable.

A preferred embodiment of the denture securing apparatus according to the invention comprises a plurality of implant pins or screws which are inserted into the mandible or jaw bone in the mouth of a denture wearer at predetermined locations. Each of the implant screws includes a head portion which, after securing the screw in the jaw bone, protrudes from the gingival or gum. The head of the screws has a bell-like shape and includes a recess or track extending circumferentially thereabout between the extreme leading end of the pin and the shank thereof. Mating cap members are embedded in the denture to be secured in the mouth of the wearer. The cap members are joined by rigid linking support members so that the interconnected cap members work as a unit structure within the denture to provide rigidity and strength thereto. Each cap member is shaped complementarily to that of the head portion of the implant screws and is of a size to receive the head portion of a corresponding implant screw. Each of the cap members includes an auxiliary chamber formed therewith. An opening is provided 3,514,858 Patented June 2, 1970 in the wall of the cap member for communication between the chamber and the interior of the cap member. A retractible, spring biased ball bearing is provided in the chamber; the ball bearing having a diameter slightly larger than the opening so that the ball bearing may protrude into the interior of the cap member but not enter thereinto fully. An adjustable helical spring member is provided in the auxiliary chamber to produce tension against the ball bearing. Upon joining the mating cap members and pin members respective ball bearings roll along the outer surface of the heads of the pin members, against the tension of corresponding springs, until they engage respective recesses in the pin members thereby to secure the denture to the pin members and in the mouth of the wearer. Adjustment of the tension of the coiled springs, causes the force exerted by each of the ball bearings on the head of a corresponding pin member, while being inserted and removed, to be greater or lesser in effect, controlling the holding force of the denture. The denture is easily removed from within the mouth by the application of a sufficient force to the denture away from the pin members, thereby to cause the ball bearings to become disengaged from respective recesses.

DESCRIPTION OF THE DRAWINGS A better understanding of the present invention and its organization and construction may be had by referring to the accompanying drawings wherein:

FIG. 1 is an exploded perspective view of a lower denture being secured in the mouth of a denture wearer through the use of denture securing apparatus according to the invention;

FIG. 2 is an enlarged exploded view of an implant screw and cap member arrangement used in the dental securing apparatus according to the invention;

FIG. 3 is a top plan view of a denture including mounted therein a unit cap structure comprised of a plurality of interconnected cap members according to the invention; and

FIG. 4 is a bottom plan view of the denture of FIG. 3 shown positioned in the mouth of a denture wearer.

DETAH .ED DESCRIPTION Referring now to the drawings, and in particular to FIG. 1 thereof, there is shown a denture generally designated by the numeral 10, herein a lower denture, which is to be received in the lower mouth 12 of a denture wearer (FIG. 3) through the use of denture retaining apparatus designated by the numeral 14, according to the invention.

The denture 10 includes the usual base support 16 and artificial teeth, such as 18, mounted thereon.

Embedded in the lower mouth 12 and extending outwardly from the gingival or gum 20 thereof, and located at predetermined sites 26 therealong, are implant pins or screws 24 according to the invention. The implant screws 24 which will be described in greater detail hereinafter are inserted through a prepared aperture such as 28 at each of the sites 26, and are screwed into the mandible or jaw bone 22, so as to provide a rigid support for the denture 10.

Mounted within the denture 10, is a unit structure 30 comprising a plurality of cap members 32 which are interconnected by rigid linking members 34. The structure 30 as well as the cap members will further be described in greater detail hereinafter.

Upon placing the denture 10 downwardly in the lower mouth 12, the cap members receive the corresponding implant screws to retain the denture in the mouth of the wearer.

Turning now to FIG. 2 of the drawings, there is illustrated therein an enlarged exploded view of a single implant screw 24 and mating cap member 32.

The implant screw 24, which is constructed preferably of a chromium cobalt metal, and is cast therefrom, includes a threaded end 36, a central portion 38 and a head portion 40. The threaded end 36 is used to screw the pin 24 into an aperture 28 drilled through the two layers, cortical or hard 22a and meshy 22b of the mandible 22 to secure the implant pin in the mouth of the denture wearer.

The lower threaded end portion 44 of the implant screw includes a plurality of random holes 42 extending therethrough. The holes have been provided to allow for the growth of the meshy bone layer 22b of the mandible or jaw bone 22 therethrough after the pin is in place to strengthen the retentive hold of the pin in the mouth. The upper threaded end portion 46 of the threaded end 36 includes no holes since it extends only into the hard or cortical layer 220, of the bone. The main holding force of the implant screws 24, however, is primarily gained from the last mentioned engagement of the threaded end 36 and the cortical bone layer 22a.

When in place in the lower mouth, the central portion 38 of the implant screw 24, which has an inwardly curved surface 39 gradually tapering toward the threaded end 36 of the screw, extends through the gingival or gum 20. Because of the inwardly curved tapered surface 39, easy entry into the gingival layer is provided as the implant pin is screwed into the mouth.

If desired, the central portion may be provided with a plurality of openings (not shown) extending therethrough. The openings allow for the growth of the gum tissue through the implant pin to ensure the prevention of exposure of the central portion of the pin after the denture is in place in the mouth. These openings however, are not necessary to the invention as illustrated herein. Other types or arrangements of openings may also be provided. In some cases, openings of the type which allow the gum to be sutured through the pin may be formed in the central portion; however, if the openings are too great the structural strength of the screws 24 will be reduced.

The head portion 40 of the implant screw is specially designed having a bell-like appearance with a substantially parabolic axial cross sectional shape. At a location approximately one-third of the distance from the extreme leading end or tip of the screw head toward the line 52 separating the central portion 38 and the head portion 40, there is formed a recess or track 52. The recess extends completely about the head portion. The purpose and function of the recess 52 will be described hereinafter.

The leading end 50 of the screw head portion 40, includes a cut 54 to allow for the use of an L-shaped screw driver to drive the implant screw 24 into the jaw bone of a denture wearer. The cut 54 may be a criss-cross cut so that a Phillips type screw driver may be used therewith; a Phillips screw driver being less likely to burr the sides of the cut 54 when driving the screw 24 into the mouth. The outer surface 56 of the head portion 40 is smooth so as to allow for ease in joining the mating cap member 32 therewith.

As menioned heretofore, the implant screws such as 24 are preferably cast of a chromium cobalt metal and are produced in various sizes to accommodate individuals whose jaw constructiondilfer. It is preferred that the threaded portion of the screw 24 be provided in three sizes; long, medium and short, the central portion 38 likewise may be made in three sizes, governed by the thickness of the gum, i.e. narrow, medium or thick and the head portions can likewise be constructed in two sizes; i.e. short or regular. The selection of the particular screw size is determined through X-rays of the mouth of the denture wearer so that a comfortable fit is ensured.

A single cap member 32 shown in FIG. 2, also constructed preferably of chromium cobalt metal, is dimensioned complementarily to the head portion 40 of the implant screw 24, also having a parabolic cross sectional shape, with an interior dimension adapted so that the cap member may receive, in mating engagement, head portion 40. The surface 58 of the interior 59 of the cap member is smooth like the outer surface 56 of the head portion of screw 24 to ensure ease in mating. The outer surface 60 of the cap member, however is roughened to facilitate the adhesion to denture base material.

At one point along the exterior of the cap member, there is formed integrally therewith an auxiliary housing structure 64. The formation of the structure 64 provides, between the exterior surface 60 of the cap member and the interior surface of wall 66 of the structure 64, a chamber 68. An opening in the wall of the cap member provides communication between the chamber and cap member interior.

Mounted within the chamber 68 is retractible bearing means taking the form of a spring biased ball bearing 72, the diameter of which is such that the ball bearing is not permitted to pass through the opening 70 from chamber 68 into the interior 59 of the cap member 32. Only a portion of the ball bearing is able to protrude into interior 59. Also located in the chamber 68 is a biasing coiled or helical spring member 74 which is used to urge the ball bearing toward opening 70. The open end 76 of the chamber 68 is threaded and a complementarily threaded member 78 is screwed thereinto; the member 78 providing an adjustable force against spring 74 and in turn ball bearing 72 in accordance with the turning thereof into chamber '68.

As mentioned heretofore, upon placing the denture 10 of FIG. 1 into the mouth of the wearer wherein implant screws 24 have been secured, the ball bearing 72 of each cap member 32 engages the outer surface 56 of a corresponding head portion 40 of a screw 24. As additional downward pressure is applied by the denture wearer inserting the denture, the ball bearings are pushed inwardly through opening 70 into chamber 64 until the ball bearings become aligned with corresponding re cesses or tracks 52. At this time, the ball bearings, due to the forces of helical springs 74, are urged outwardly of the chamber into locking engagement with respective recesses 52 of head portions 40 of screws 24.

In the event a greater force on ball bearings 72 is desired, the tension adjusting screw 78 is turned into threaded opening 76, causing the helical or coiled springs 74 to compress and provide greater force against ball bearing 72.

Referring now to FIG. 3 of the drawings, there is shown therein a bottom plan view of the denture 10 comprising the unit cap member structure 30 including individual cap members 32 embedded into the material, and interconnected by rigid linking members 34.

It will be noted, the denture 10 herein illustrated is a lower denture with the base portion 16 thereof having a recess channel extending along the lower surface 81 thereof to accommodate the gum or gingival ridge in the mouth 12 of the denture wearer. The denture includes the base and teeth portions formed of the usual denture material and is constructed in the usual manner.

Looking now closely at FIG. 3, the cap members 32, spaced about the denture 10 along gum accommodating recesses or channels 80, are interconnected by rigid lengths of chromium cobalt or the like metal rods generally designated as 34. The rods are attached to the cap members by soldering or other suitable means. Rods 34a and 340, which are shaped to conform to the curva ture of the ridge, extend between the cap members placed at the molar or posterior position in the mouth (32a and 32d) and those positioned near the cuspid or anterior section of the mouth (32b and 32c), respectively. A third rod or linking member 34b interconnects the anterior cap member 32b and 320. Rod 34b likewise is shaped to conform to the curvature of the ridge. The rods, as

indicated in dotted lines, in FIG. 3, are embedded into the denture material, providing structural support thereto, as well as uniting the cap member 32 to form the unit support structure 30.

As seen in FIG. 4, wherein the denture of FIG. 3 is shown mounted in the mouth of a denture wearer, at the portion thereof sectioned and revealing outer surface 60 of the cap member 32d, the cap member, extends into a false tooth 18, mounted on the base portion of the denture 10. This can best be seen in FIG. 2 wherein the tooth 62 is shown to have an interior dimension complementary to that of the cap exterior to receive cap member 32 therein. As mentioned heretofore, the outer surface 60 of the cap member is roughened to ensure the retention of the cap member to the denture material.

At another section taken in FIG. 4 the entire cap member and denture material has been removed to reveal the top of head portion 40 of animplant pin extending from the gum 20 of the mouth 12. This view is shown merely to illustrate the criss-cross cut for accommodating a Phillips screw driver used to position the implant screws 24 into the jaw bone.

For purposes of affording a more complete understanding of the invention, it is advantageous now to provide a description of the manner in which the component parts thus described are used to provide a denture wearer with the benefit of the instant apparatus.

As will be noted from the drawings, in particular FIG. 1 thereof, it is preferred to use four implant screws 24 to retain a denture in the denture wearers mouth. Before proceeding with the implants, the size of each of the pins or screws is determined by X-rays or other means to reveal the mandible size (i.e. vertical distance thereinto to reach the mandibular canal), the gingival thickness, etc.

After the above is determined, implant pin sizes, as described heretofore, are chosen. The patient is anesthetized on both sides of the mouth and four suitable sites 26 are chosen in the mouth. The posterior or rear sites should be situated in the most horizontal area of the first and second molar position. The anterior sites should be in the cuspid region, also along a horizontal plane or as nearly horizontal as possible.

When the sites are chosen, the gum is cut thereabout and with a standard surgical drill, four apertures or holes are drilled into the mandible or jaw bone, through the hard or cortical bone layer.

The implant pins are screwed into respective apertures at each site until the central portion 38 thereof is lodged in the gum. Because of the inwardly curved surface 39 of central portion 38 of the pin, which is tapered toward the threaded end portion 36, no undercutting of the gum occurs during the screwing in of the pin.

A cap member 32 is positioned over each of the head portions 40 of a corresponding implant pin, with the ball bearings removed from chambers 64. An impression tray is selected and with a mix of quick setting algimate, an impression of the cap member is made. The impression is poured up in a heat resistant plaster, and the cap members are joined together by soldering thereto linking members 34 (FIG. 1) of chromium cobalt metal, to form a unit structure 30. The last step is the formation of the denture itself. An impression is made in the usual manner with the structure 30 in place on the implant pins 24, and the denture material is then poured and allowed to set with the unit structure embedded therein.

Once the ball bearings have been replaced in the cap member, the denture wearer is able to position the denture in his mouth with no worry as to wobbly or unstable dentures.

It should be understood that a denture provided with apparatus according to the invention is easily removed from position within the mouth of the wearer. The denture wearer merely exerts a slight force on the denture away from the implant pins, so that the ball bearings 72, FIG. 2, mounted in the cap members 32, are released from. engagement with recesses or tracks 52. By means of adjusting screws 78 (FIG. 2) the force required to position the denture into the mouth and to remove the denture therefrom can be adjusted.

In addition to changing the force required for insertion and removal of the denture 10 in the mouth, the adjustment of screws 78 also serves to permit minute movement of the denture in the mouth to assimilate the action of normal teeth when the denture wearer chews food. This action which is directed against the spring loaded ball bearings aids in providing comfort to the denture wearer. The ball bearings also provide a further function, which is to absorb forces in the mouth-ordinarily applied directly against the denture. In this manner the ball bearin'gs serve as a cushioning mechanism against lateral movement of the denture in the mouth.

Thus, the dental apparatus according to the instant invention provides a practical, efficient means for truly securing a denture in the mouth of a denture wearer. The apparatus is able to be mounted within the denture wearers mouth with little or no discomfort to him. Furthermore, the denture is easily placed in and removed from the denture wearers mouth without difficulty and without special tools or equipment.

The dental apparatus according to the instant invention, while being used primarily for retaining full dentures in the mouth of a wearer, may also be used for securing single false teeth in the mouth.

In a case wherein a single tooth has been extracted from the mouth, an implant pin is implanted in the jaw bone at the location of the extraction in the same manner as explained heretofore in regard to the denture. A single cap member is embedded into a false tooth and the cap member is then snapped into position over the head portion of the implant pin. The single false tooth, like the denture is easily removable from the month without special tools or other means.

While a particular embodiment of the invention has been shown and described, it should be understood that the invention is not limited thereto since many modifications may be made. It is therefore contemplated to cover by the present application any and all such modifications as fall within the true spirit and scope of the appended claims.

What is claimed is:

1. Apparatus for retaining a denture in the mouth of a denture wearer, comprising a plurality of implant pins adapted to be mounted at predetermined locations in the jaw bone of said denture wearer, each of said pins including a threaded end portion and a head portion, said threaded end portion being screwable into an aperture provided in the jaw bone with said head portion extending outwardly therefrom into the mouth, said head portion including a recess formed therein; and a plurality of cap members mounted in said denture, each of said cap members having a shape complementary to that of the head portion of said pins and arranged so as to receive a respective head portion therein upon positioning said denture into the mouth of said denture wearer, each of said cap members including retractib'le bearing means for engagement in a recess of a head portion of a respective implant pin for removably securing said denture to said implant pins, said retractible bearing means including a ball bearing mounted in said cap member, said ball bearing being resiliently biased toward and extending at least partially into the interior of said cap member for receipt in said recess upon mounting said denture into the mouth of said wearer.

2. Apparatus as claimed in claim 1 wherein said cap members are joined by rigid linking members, thereby to form a unit structure, said structure being embedded in said denture to provide added strength and stability thereto.

3. Apparatus as claimed in claim 1 wherein said recess formed in the head portion of each of said implant pins extends circumferentially thereabout, wherein each of said cap members includes an auxiliary housing, and an opening therein to provide communication between said housing and said cap member, said spring-loaded ball bearing being mounted within said housing, the ball bearing being of a size slightly larger than said opening, thereby to permit a portion of said ball bearing to extend from said housing into the interior of said cap member for engagement within the recess of said implant pin, 'Without passing completely through said opening, and wherein said housing includes therein adjustment means for adjusting the pressure applied by said ball bearing thereby to provide greater or lesser force for holding said denture in the mouth of said denture wearer.

4. Apparatus as claimed in claim 3 wherein said head portion has an axial cross sectional shape of a parabola and a smooth outer surface, wherein said auxiliary housing is formed integrally with said cap member and includes an internally threaded portion, and wherein said adjustment means includes a screw member being dimensioned and threaded complementarily to the threaded portion of said housing for receipt therein, thereby to adjust the tensioning of said spring against said ball bearmg.

5. Apparatus as claimed in claim 1 wherein said plurality of implant pins comprises four implant pins mounted at predetermined locations in the mouth of said denture wearer, two of said pins being mounted at the molar position at each side of the mouth and the remaining two pins being mounted at the cuspid position at each side of the mouth, and wherein four cap members are mounted in said denture at corresponding locations for receipt of said implant pins upon insertion of said denture into the mouth.

6. Apparatus as claimed in claim 4 wherein a portion of the threaded end portion of each of said implant pins includes a plurality of random holes therethrough to permit the growth of'bony material therein subsequent to the mounting of said pins in said jaw bone.

'7. A removable artificial denture apparatus comprising a plurality of implant pins each anchorable in the mouth and each including a threaded end portion and a head portion, said threaded end portion being screwable into the jaw bone with said head portion extending outwardly therebeyond into the mouth, a denture and a plurality of cap members mounted in said denture, each of said cap members having a shape complementary to that of the head portion of said implant pins and being dimensioned to receive a respective one of said head portions therein, the head portion of each of said implant pins including a recess therein extending circumferentially thereabout and each of said cap members including a spring-loaded ball bearing mounted therein, said ball bearing being resiliently urged toward and extending at least partially into the interior of said cap member for receipt in a corresponding recess, thereby to removably secure said denture in the mouth upon the positioning of the former into the latter.

8. Artificial denture apparatus as claimed in claim 7 wherein said cap members are joined by rigid linking members, thereby to form a unit structure, said unit structure being embedded in said denture and wherein each of said implant pins includes a central portion between said head and threaded portions, said central por tion being positionable within the gum of said mouth.

9. Artificial denture apparatus as claimed in claim 8 wherein said central portion of each implant pin has a smooth, inwardly cunved surface, tapering toward the threaded end portion of each of said implant pins, whereby upon the insertion of said pin into said jaw bone, said central portion enters said gum with substantially no binding of the latter. 10. Removable artificial false tooth means comprising an implant pin anchorable in the mouth and including a lower end portion and a head portion, said lower end portion being mountable into the jaw bone with said head portion extending outwardly therefrom into the mouth, false tooth means and a cap member mounted in said false tooth means, said cap member having a shape complementary to that of the head portion of said implant pin and being dimensioned to receive said head portion therein, the head portion of said implant pin including a recess therein, and said cap member including retractible bearing means mounted therein, said bearing means including a ball bearing being resiliently biased toward and extending at least partially into the interior of said cap member for receipt in said recess, thereby to removably secure said false tooth means in the mouth upon the positioning of former into the latter.

11. Removable artificial false tooth means as claimed in claim 10 wherein said ball bearing is spring-loaded and wherein said recess extends circumferentially about the head portion of said implant pin.

References Cited UNITED STATES PATENTS 2,112,007 3/1938 Adams 32-2 2,347,567 4/1944 Kresse 32-10 2,644,231 7/1953 Brennan 3210 3,085,334 4/1963 Bischof 3210 ROBERT PESHOCK, Primary Examiner U.S. Cl. X.R. 325 

